Copper-silver dual-component metal electroplating solution and electroplating method for semiconductor wire

Abstract

A copper-silver dual-component metal electroplating solution includes copper methanesulfonate, silver methanesulfonate, methanesulfonic acid, chlorine ions, and water. An electroplating method for forming a copper-silver dual-component metal by using such an electroplating solution, the steps of which includes (a) contacting the copper-silver dual-component metal electroplating solution with a substrate; (b) applying an operating voltage, the current density of which is controlled to be between 0.1 and 2 ASD in order to carry out electroplating on the substrate. Therefore, the electroplating solution has environmental characteristics, such as less poisoning hazards, through the design of methanesulfonic acid and methanesulfonate electroplating solution. Also, the potential and the current are adjusted during the electroplating in order to obtain a copper-silver dual-component metal plating layer with a specific silver content.

What is claimed is: 
     
       1. A copper-silver dual-component metal electroplating solution, including copper methanesulfonate, silver methanesulfonate, methanesulfonic acid, chlorine ions, a thiourea compound and water
 wherein the molarity of chlorine ions is between 0.1 and 3 mM; 
 the thiourea compound, which is (R 1 R 2 N)(R 3 R 4 N)C═S, wherein R 1 , R 2 , R 3  and R 4  are the same or different, and are each a hydrogen atom or a hydrocarbon; 
 and wherein the molarity of the thiourea compound is 5 to 10 times greater than that of silver methanesulfonate. 
 
     
     
       2. The copper-silver dual-component metal electroplating solution of  claim 1 , wherein the molarity of copper methanesulfonate is between 0.05 and 0.8 M. 
     
     
       3. The copper-silver dual-component metal electroplating solution of  claim 1 , wherein the molarity of silver methanesulfonate is between 0.1 and 6 mM. 
     
     
       4. The copper-silver dual-component metal electroplating solution of  claim 1 , wherein the thiourea compound is selected from the group consisting of thiourea, diethyl thiourea, phenyl thiourea, allyl thiourea and diphenyl thiourea. 
     
     
       5. The copper-silver dual-component metal electroplating solution of  claim 1 , further comprising a surfactant. 
     
     
       6. The copper-silver dual-component metal electroplating solution of  claim 4 , further comprising a surfactant. 
     
     
       7. The copper-silver dual-component metal electroplating solution of  claim 5 , wherein the surfactant is a polymer compound with a molecular weight between 2,000 and 20,000. 
     
     
       8. The copper-silver dual-component metal electroplating solution of  claim 6 , wherein the surfactant is a polymer compound with a molecular weight between 2,000 and 20,000. 
     
     
       9. The copper-silver dual-component metal electroplating solution of  claim 5 , wherein the surfactant is selected from the group consisting of polyethylene glycol and polypropylene glycol. 
     
     
       10. The copper-silver dual-component metal electroplating solution of  claim 6 , wherein the surfactant is selected from the group consisting of polyethylene glycol and polypropylene glycol. 
     
     
       11. An electroplating method of a copper-silver dual-component metal, including the steps of:
 (a) contacting the copper-silver dual-component metal electroplating solution of  claim 1  with a substrate; 
 (b) applying an operating voltage, the current density of which is controlled to be between 0.1 and 2 ASD in order to carry out electroplating on the substrate.